Adoptive cellular immunotherapy is a treatment that employs biological reagents to effect an immune-mediated response. Currently, most adoptive immunotherapies are autolymphocyte therapies (ALT) directed to treatments using the patient's own immune cells. These therapies involve processing the patient's own lymphocytes to either enhance the immune cell mediated response or to recognize specific antigens or foreign substances in the body, including the cancer cells. The treatments are accomplished by removing the patient's lymphocytes and exposing these cells in vitro to biologics and drugs to activate the immune function of the cells. Once the autologous cells are activated, these ex vivo activated cells are reinfused into the patient to enhance the immune system to treat various forms of cancer, infectious diseases, autoimmune diseases or immune deficiency diseases.
Osband et al., The Lancet 335:994-998 (1990), describe an autolymphocyte therapy to treat metastatic renal cell carcinoma (mRCC). In this procedure, an autologous cytokine mixture is prepared using the patient's peripheral blood mononuclear T cells. Then, autologous lymphocytes are stimulated with the autologous cytokine mixture and with various activating agents, such as antibodies against T cell surface antigens. Once the autologous lymphocytes are activated, the cells are reinfused into the patient to enhance the immune response.
Another autolymphocyte therapy in the treatment of kidney cancer is the processing of a cancer patient's natural killer (NK) cells, with interleukin-2 (IL-2). This processing stimulates the immune cells to proliferate. The activated NK cells are then reinfused into the cancer patient, where the infused cells proliferate and mediate an immune response. Feinfeld et al., "Interstitial nephritis in a patient receiving adoptive immunotherapy with recombinant interleukin-2 and lymphokine-activated killer cells," American Journal of Nephrology 11:489-492 (1991).
Two additional autolymphocyte therapies are lymphokine-activated killer cell (LAK) therapy and tumor-infiltrating lymphocyte (TIL) therapy. LAK therapy involves the in vitro generation of LAK cells by culturing autologous peripheral blood leukocytes in high concentrations of IL-2. The LAK cells are then reinfused into the cancer patient in a treatment that may also involves infusion of IL-2. Rosenberg and Lotze, "Cancer immunotherapy using interleukin-2 and interleukin-2 activated lymphocytes," Annual Review of Immunology 4:681-709 (1986). TIL therapy involves the generation of LAK cells from mononuclear cells originally derived from the inflammatory infiltrating cells present in and around solid tumors, obtained from surgical resection specimens. The rationale for this appropriate is that TILs may be enriched for tumor-specific killer cells. The processed TIL cells are then reinfused into the patient to promote an immune mediated response to the tumor cells. Rosenberg et al., "A new approach to the adoptive immunotherapy of cancer with tumor-infiltrating lymphocytes," Science 233:1318-1321 (1986).
An autolymphocyte therapy using tumor cells for the treatment of melanoma involves the in vitro stimulation and culturing of peripheral lymphocytes, or lymph node cells, together with the patient's melanoma cells or with HLA-A region matched allogeneic melanoma. The immune cells are repeatedly stimulated with the tumor cells and IL-2, and then further induced and amplified with phorbol dibutyrate and ionomycin. Darrow et al., "Modulation of In Vitro Autologous Melanoma-Specific Cytotoxic T-Cell Responses by Phorbol Dibutyrate and Ionomycin," Cellular Immunology 125:508-517 (1990).
Yet another autolymphocyte therapy is a procedure called autologous bone marrow transplant (BMT) used for treating leukemia, testicular cancer and lymphoma. Bone marrow is removed from the cancer patient prior to chemotherapy. The bone marrow is processed and cryopreserved. Following chemotherapy, the patient then receives the autologous treated bone marrow. R. Champlin and R. P. Gale, "Bone Marrow Transplantation: Its Biology and Role as Treatment for Acute and Chronic Leukemias; in Normal and Neoplastic Blood Cells: From Genes to Therapy, C. Peschle, Editor, Annals of the New York Academy of Sciences 511:447-458 (1987).
In addition to the cancer immunotherapies, adoptive immunotherapy has applications for deficiency or dysfunction of T cells associated with several diseases and conditions. Viral infections that respond to IFN-alpha include recurrent herpesvirus (HSV, VZV, CMV), hepatitis B virus, and papillomavirus. Spiegel, R. J., "The alpha interferons: Clinical overview." Seminars in Oncology 14:1 (1987). The patients suffering from these viral infections may have their lymphocytes processed using an autolymphocyte therapy that stimulates the production of cytokines.
ALT is also being evaluated in the treatment of patients infected with HIV. Various immune system defects and abnormalities are associated with AIDS and HIV infection, most notably, there is a functional deficiency in CD4+T cells. However, induction of T cell mediated responses could contribute to the accelerated destruction of the host immune system, since activation of T cells is required for HIV entry into CD4+ cells. Although the immune mechanism is still being evaluated, some reports indicate that CD8+ T cells can play an important role in the control of HIV production. O. Martinez-Maza, "HIV-Induced Immune Dysfunction and AIDS-Associated Neoplasms," in Biological Approaches to Cancer Treatment: Biomodulation, M. Mitchell, Editor, McGraw-Hill, Inc., Chapter 9, pages 181-204 (1993).
Periodontal diseases may also be treated with adoptive immunotherapy. Although gingivitis and periodontitis are caused by dental bacterial plaque, there is a reluctance to treat this disease with antibiotics because of the problems with antibiotic-resistant strains. Lymphocytes from individuals with periodontal disease may be treated in vitro with general immune enhancing mitogens or with dental plaque antigens to mediate an immune response. Engel et al., "Mitogen-induced hyperproliferation response of peripheral blood mononuclear cells from patients with severe generalized periodontitis: Lack of correlation with proportions of T cells and T cell subsets," Clinical Immunology and Immunopathology 30:374 (1984).
Additionally, adoptive immunotherapy may be used to generally boost the immune system by improving an immune cell mediated response. With age, the functions of the immune system show some evidence of decline. For instance, the DTH response, an immune cell mediated event, has been documented to be reduced with age. Miller, "Age-associated decline in precursor frequency for different cell-mediated reactions with preservation of helper and cytotoxic effect per precursor cell," Journal of Immunology 132:63 (1984) and Saltzman and Peterson, "Immunodeficiency of the elderly," Review of Infectious Diseases 9:127 (1987).
One of the major challenges associated with adoptive immunotherapy is the identification of in vitro assays that are useful in predicting in vivo efficacy. Most notable in this regard is with LAK therapies in the lack of correlation between the cytotoxic function of LAK cells and the in vivo outcome. As reported in Biological Approaches to Cancer Treatment: Biomodulation (Mitchell, Ed., McGraw-Hill, Inc. (1993)), the results of LAK and IL-2 therapies give conflicting conclusions: In a protocol for treating patients with processed LAK cells and a low dose of IL-2, with one study there was a significant patient response rate and reduced toxicity. Yet, a similar trial resulted in greater patient toxicity and fewer responses (Rubin and Lotze, "Adoptive Cellular Immunotherapy of Cancer," Chapter 16, pages 379-409, supra.)
Since adoptive immunotherapy is based primarily on the infusion of in vitro processed immune cells into the patient, it is a goal of researchers to develop an accurate measurement of in vitro activity of the processed immune cells which can be correlated with in vivo efficacy. Development of this assay is hampered by activation mechanisms in lymphocytes. T lymphocytes, for example, require at least two different signals, generated by two different cell surface-binding events, for full activation. Proliferation, in response to antigen recognition, is mediated primarily by all autocrine growth pathway, in which the responding T cell secretes its own growth-promoting cytokines and also expresses cell surface receptors for these cytokines. The first signal is the binding of the T cell receptor (TCR):CD3 complex to antigen processed and presented in association with MHC class II antigen on the surface of antigen presenting cells (APCs). The second signal may be triggered by activated APCs either as secreted cytokines produced by the APCs binding to specific receptors on T cells or by cell-cell interaction through accessory membrane bound molecules.
These two signals can be replicated in vitro by the combination of protein kinase C (PKC) activators, such as phorbol esters, and calcium ionophores, such as ionomycin, which increase cytoplasmic calcium concentrations. Neither PKC activators nor calcium ionophores are sufficient alone for full T cell activation.
A number of other mitogens have been used with in vitro cultures to activate and assess human lymphocyte function. Some lectins, such as phytohemagglutinin (PHA) and concanavalin A (Con A), activate T lymphocytes. Other lectins, such as pokeweed mitogen (PWM) activate B lymphoctyes. These mitogens act in a cell-cell dependent manner or require antigen presenting cells (APCs) to activate the lymphoctyes. The degree of lymphocyte activation in vitro is also a function of the cellular regulatory influences present in the culture. Suppressor or helper T, B, and mononuclear cells are all capable of modifying the final degree of proliferation in the specifically stimulated cell population. Some mitogens, particularly Con A, are known to activate suppressor T cells, which may markedly reduce the proliferative response in these cultures. Due to the variability in the nonspecific stimulation of lymphocytes with these mitogens, their use as stimulants for lymphocyte activation in in vitro assays for adoptive cell immunotherapy is unsatisfactory. Since adoptive immunotherapy is based principally on the infusion of modified or activated immune cells into the patient, an accurate in vitro assay measuring the degree of activation of the processed immune cell would be an important first step in correlating in vitro response with in vivo efficacy.